Research On A New Principle Of The Distance Relay

Distance protection is the main protection mode of high voltage transmission lines in complex electric network all along.So the research on the practical problem is necessary.The influence on distance relays which caused by fault resistance is analyzed in this paper,also present solutions are introduced and compared. As an innovation and main research work of this paper,a fault distance measured principle using on terminal base frequency electric quantities is proposed.This principle based on relationship of the voltage and current at fault point,and it is independent on fault resistance,immune to load current and source impedance.Specific forms for phase to phase and phase to ground fault are described.Verified by various kinds of faults simulations,including high resistance fault to ground,the proposed principle has high accuracy.Assuming fault phase is selected correctly,a fault distance measured principle which using one terminal electric quantities from one line is proposed.It is immune to load current,source impedance and fault resistance. High accuracy is obtained at various kinds of faults simulations.